Consider splitting the docs of `value_box()` and `showcase_*()` functions?

[etiennebacher]

Hello, this is a request to clarify the documentation of "Value box". This page contains the definition of five functions that can be split in two categories:

• value boxes functions: value_box() and value_box_theme()
• showcase functions: showcase_left_center(), showcase_top_right(), showcase_bottom()

These two groups share relatively few arguments but in cumulative there are 16 arguments documented. In several occasions I thought one of the arguments could be used in one the groups of functions mentioned above when it actually didn't. This is not a big problem, it is just annoying to go back and forth between the function definition and the argument list to know which argument is related to which function.

Besides, the showcase functions are not present at all in examples. Would you consider moving the showcase functions to their own page and link to this page from the value box page?

[gadenbuie]

Thanks for the issue, @etiennebacher, you raise some good points. Would you be interested in submitting a PR to make the change?